This invention pertains to the art of fluid valves and more particularly to a diaphragm valve.
The invention is particularly applicable to a diaphragm valve for use in biotechnological applications and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be advantageously employed in other environments and applications.
Prior diaphragm valves have been deficient in two primary areas, namely, (i) cycle life and (ii) ease of maintenance and/or replacement. Cycle life is closely dependent on the strength of the diaphragm, particularly the flexural strength of the diaphragm. Some prior valves have utilized a metallic diaphragm due to its high strength. Other valves have utilized an elastomeric diaphragm due to its superior flexure and sealing properties. Still others have attempted to strengthen elastomeric-type diaphragms through use of a composite diaphragm having elastomers of different strengths.
Even with continued improvements in diaphragm valve designs, overall cycle life is still dependent on the strength of the diaphragm. Oftentimes, the remainder of the valve components still have a substantial useful life but changeover or replacement of the worn component, i.e., the diaphragm, is still necessary. Prior arrangements simply have not adequately addressed the problem of repeated maintenance or replacement. That is, if the valve must be repaired or replaced the various valve components have not been designed to aid in cleaning, replacement, and subsequent reassembly.
Another frequently encountered problem is the limited space availability for the valve in the associated fluid system. Typically, process lines of the fluid system are closely spaced together or positioned closely adjacent other equipment or structures. A valve can only occupy a minimum amount of space and must be compact enough to operate in hard-to-reach places. Thus, compactness is another primary requirement in valve design without compromising valve performance.